Assessment of Fatigue and Corrosion Effects on Coating from the SMAW Process

This study examines how wear impacts the mechanical properties of the interface between weld overlay Inconel 182 and a 25CD4 substrate when using the SMAW process. The microstructure at the interface of the Inconel 182 /25CD4 substrate mainly featured columnar Ni-γ, with a gradient of Ni ;Cr and Fe, elements diffusing from the melting limits to the type II boundary close to the interface. A scratch resistance test was carried out on the interface to evaluate the adhesion and wear resistance of the Inconel 182 overlay and the 25CD4 substrate. The test was performed under a constant load of approximately 100 N, with a spherical indenter of 0.6 mm radius, creating a (5 mm) scratch length over a period of 50 s at a scratch speed (0.1 mm/s). There are two zones. A reloading zone (Inconel 182) with totally Viscoplastic contact another zone which is that of the substrate presenting elastic deformations at the same time. The variation of the coefficient of friction over time across the substrate/recharge interface reveals three distinct zones. The coefficient of friction increases rapidly until it reaches a maximum of 0.63, corresponding to a zone of high roughness (inter-diffusion zone). The electrochemical characteristics of the Inconel 182 overlay and the 25CD4 substrate in a 3.5% NaCl solution revealed evidence of galvanic corrosion.